Pot Metal Advice

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Marty Bufalini
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Pot Metal Advice

Post by Marty Bufalini » Wed Jul 10, 2019 6:16 pm

I've got a pot metal body carburetor that has a shaft extending through the middle of the float bowl with a metal nut threaded onto the pot metal shaft with the nut holding the float bowl onto the carb body. I hope that made sense.

If that shaft breaks, the rare (Scoe) carb is ruined.

I've been hitting the nut with PB Blaster but I'm leery about taking a wrench to it.

Do you know if I can heat the metal nut with a torch without hurting the pot metal shaft?

Or do you have any other advice/ideas?

Thanks in advance.


Rich Bingham
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Re: Pot Metal Advice

Post by Rich Bingham » Wed Jul 10, 2019 7:41 pm

Pictures would help, Marty. I'm guessing by a "metal nut" you mean it's steel or brass as opposed to pot metal ? "Pot metal" is a non-specific term we usually understand to mean a low temp lead based alloy, usually some kind of soup composed of lead, zinc, tin, antimony etc. they will melt around 500-700 F and slump at cooler temps, so be very cautious.

The bad news is that the stuff is prone to corrode in contact with dissimilar metals. Personally I've never seen that corroded pot metal responds to rust solvents. The good news is that broken pot metal items usually respond well to being repaired with JB Weld or other epoxy resins. Dunno how well that would wear in proximity to gasoline though.
"Get a horse !"


Burger in Spokane
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Re: Pot Metal Advice

Post by Burger in Spokane » Wed Jul 10, 2019 10:05 pm

Rich is correct about pot metal/heat/corrosion/etc. You might try making a shield to
keep the torch flame off the pot metal and try to heat the other part to break the grip
of the corrosion.

Thinking of this another way, how complicated is the shape of this pot metal bowl ?
Could it be replicated using brass ? I am currently having a piece of 1890 era unobtainium
made out of brass, turned down from solid stock. Some times one needs a Plan B when
it comes to impossible parts.
More people are doing it today than ever before !

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Duey_C
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Re: Pot Metal Advice

Post by Duey_C » Wed Jul 10, 2019 10:21 pm

I'm NO expert with this stuff but know when it starts going bad, it crumbles apart. like when I tried to remove the float bowl cover on the buddy's '23 Overland Baby's carb. I removed the two screws and gently lifted the cover off and it literally crumbled in my fingers!
Not a scare tactic Marty. Just saying this particular float bowl cover was done for.
My first notion would be to drill the nut to pieces and split it off of the carb's bowl shaft. I thought it made perfect sense. :)
The model railroad groups usually just call it Zamac and it's been used widely for locomotive frames and bodies like on my old Mantua engines. That particular stuff is holding up well on the Mantua's even near 70 years later.
Other brands have a lot of problems as the "toys" age.
The typical flaking and crumbling and final failure is always looming in our heads. One fellow wrote a good article on preservation techniques years ago. DRY DRY DRY and then dry it some more so NO moisture could possibly be present inside to the core of the material and then start letting it soak up super glue but kind of like Rich mentioned, I sure don't know if cured Cyanoacrylate will hold up to gasoline and that's AFTER you get the Scoe nut and bowl off!
Keep us posted and click us a pic if you would as I'd love to see a Scoe. Sorry for the long babble.
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Scott_Conger
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Re: Pot Metal Advice

Post by Scott_Conger » Wed Jul 10, 2019 11:05 pm

Marty, contact me via email, please.

This is for those that don't know what it looks like:
post-76866-143138587672_thumb.jpg
Scott Conger

Full Flow Float Valves - deliver fuel like Henry intended!


Rich Bingham
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Re: Pot Metal Advice

Post by Rich Bingham » Thu Jul 11, 2019 8:14 am

Thanks for the look-see Scott ! It appears the carb is copper plated ? That may help its survivability. For all the rust in the bowl, this one looks pretty good inside.
"Get a horse !"


Topic author
Marty Bufalini
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Re: Pot Metal Advice

Post by Marty Bufalini » Tue Jul 16, 2019 6:04 pm

I did it! The PB Blaster must have worked because that nut holding the bowl on came off with no breakage to the pot metal.

Thanks for all the advice.

Marty


Scott_Conger
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Re: Pot Metal Advice

Post by Scott_Conger » Tue Jul 16, 2019 6:57 pm

Good for you, Marty!

Far better outcome than I envisioned (as you are aware!)
Scott Conger

Full Flow Float Valves - deliver fuel like Henry intended!

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BuddyTheRoadster
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Re: Pot Metal Advice

Post by BuddyTheRoadster » Sun Jul 21, 2019 11:53 pm

I'm glad that PB Blaster worked for you.

FWIW, 1910s-1920s pot metal was usually awful, they had trouble with intergranular corrosion even back then, and metallurgists finally got it sorted out around 1929. Unfortunately, since pot metal takes to precision casting so well, way too many distributor bodies and carburetor parts were made out of it.

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